Analyzing the Causes of High Vibration of the Turbine Drum Rotor During Bench Tests

The results of mathematical simulation and experimental study of the dynamic behavior of the turbine drum rotor carried out because of the unsatisfactory vibration characteristics revealed during bench tests of the turbine- coupling-hydrobrake rotor system are presented. The main design features of the bench rotor system that influence its dynamic performance are considered. The spectra of frequencies and modes as well as the amplitude- frequency response of the rotor system excited because of the unbalance of the turbine rotor or the coupling span are determined. For computational purposes, software developed by the authors was used. The algorithm for mathematical simulation of rotor vibrations is based on the modal expansion method for the conservative rotor-bearings system. It is shown that the rotor can roll over the stator, which is the main cause of an emergency situation. Based on the computed and experimental results, the causes of failure of the upstream bearing are analyzed.